FIRST EXPERIMENTAL-DETERMINATION OF AN ADSORPTION SITE USING MULTIPLE WAVE-NUMBER PHOTOELECTRON DIFFRACTION PATTERNS

Angular distributions of S2p32 photoelectrons were measured for Ni(111)-p(2×2)S at seven kinetic energies between 130 and 322.5 eV. Using these data, the real space structure around the emitter is reconstructed using the multiple wave number phased-sum algorithm. The reconstructed images allow the unequivocal identification of the fcc adsorption site, with a distance from the S atoms to the top Ni layer of 1.6. This is, to our knowledge, the first example wherein the multiple wave number phased-sum method has successfully been applied to determine an adsorption site from experimental data. © 1994 The American Physical Society.